Conforming, electro-magnetic interference reducing cover for circuit components

ABSTRACT

An electronic circuit component is provided with shielding for electro-magnetic interference (“EMI”) by covering at least part of the component with a layer of electrical insulation that conforms to the shape of the surface to which the insulation is applied. At least part of the surface of the insulation is then covered by a layer of EMI shielding that conforms to the shape of the surface of the insulation to which the shielding is applied.

This application claims the benefit of U.S. provisional patentapplication 61/072,640, filed Mar. 31, 2008, which is herebyincorporated by reference herein.

BACKGROUND OF THE INVENTION

This invention relates to electronic circuitry, and more particularly toshielding that may be used around such circuitry to reduceelectro-magnetic radiation from or to such circuitry (so-calledelectro-magnetic interference or EMI).

A traditional way to reduce EMI for electronic circuitry is to placeelectrically conducting (typically metal) shielding around thecircuitry, which shielding is connected to electrical ground (i.e., asource of electrical ground potential or voltage). For example, severalelectronic circuit components that have been mounted on a printedcircuit board (“PCB”) may be placed under a metal cover or inside ametal container (“can”). A layer of electrical insulation may beincluded between the circuit components and this metal shielding toensure that the shielding cannot cause any short circuits in theelectronic circuitry by making electrical contact with that circuitry.

A possible problem with the foregoing approach is that the metalshielding is typically fabricated in advance with a predetermined sizeand shape, which size and shape the shielding retains after theshielding has been combined with the electronic circuitry to beshielded. This means that because of manufacturing tolerances for (1)the electronic circuitry, (2) the shielding, and (3) any insulation usedbetween the circuitry and the shielding, the shielding must be madesignificantly larger than the theoretical minimum size the shieldingcould have. Such results are inconsistent with the need to make manytypes of electronic devices as small as possible.

SUMMARY OF THE INVENTION

In accordance with certain possible aspects of this invention, anelectronic component may be shielded by at least partly covering it witha layer of electrical insulation that conforms to the shape of thesurface of the electronic component to which the insulation is applied.The electrical insulation is then at least partly covered by a layer ofEMI shielding that conforms to the shape of the surface of theinsulation to which the EMI shielding is applied.

Further features of the invention, its nature and various advantages,will be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified plan view of some illustrative prior artelectronic circuitry.

FIG. 2 is a simplified elevational view (partly in section along a linelike 2-2 in FIG. 1) of circuitry like that shown in FIG. 1 with otherconventional elements added.

FIG. 3 is a simplified elevational view taken along a line like 3-3 inFIG. 1, but with some possible additional features shown.

FIG. 4 is similar to FIG. 3, but shows a later stage in processing whatis shown in FIG. 3.

FIG. 5 is again similar to FIG. 4, but shows a still later stage inprocessing what is shown in FIG. 4.

FIG. 6 is a simplified elevational view taken along the line 6-6 in FIG.5.

FIG. 7 is a simplified elevational view, partly in section, of anillustrative embodiment of apparatus in accordance with the presentinvention.

FIG. 8 is a simplified plan view of another illustrative embodiment ofapparatus in accordance with the invention.

FIG. 9 is a simplified sectional view taken along the line 9-9 in FIG.8.

FIG. 10 is a view similar to FIG. 9 showing an illustrative embodimentof a later stage in use of the apparatus of FIGS. 8 and 9 in accordancewith the invention.

FIG. 11 is a simplified plan view showing an illustrative embodiment ofan intermediate stage in use of the apparatus of FIGS. 8 and 9 inaccordance with the invention.

FIG. 12 is a view similar to FIG. 8 for another illustrative embodimentin accordance with the invention.

FIG. 13 is a simplified sectional view taken along the line 13-13 inFIG. 12.

FIG. 14 is a simplified elevational view, partly in section, of anillustrative embodiment of apparatus inside processing apparatus inaccordance with the invention.

FIG. 15 is a simplified sectional view taken along the line 15-15 inFIG. 14. (Sectional portions of FIG. 14 are taken along the line 14-14in FIG. 15.)

FIG. 16 is similar to FIG. 15 for later stage apparatus inside laterstage processing apparatus in accordance with the invention.

FIG. 17 is generally similar to FIG. 15, but for other illustrativeapparatus and processing apparatus in accordance with the invention.

FIG. 18 is generally similar to FIG. 16, but for later stage apparatusand processing apparatus that may follow what is shown in FIG. 17 inaccordance with the invention.

DETAILED DESCRIPTION

Illustrative prior art electronic circuitry 10 is shown in FIG. 1 by wayof additional background. Circuitry 10 includes a sheet 20 of printedcircuit board (“PCB”) material on which several electronic circuitcomponents 30 a-d are mounted. (As used herein, the term PCB includesall forms of this general type of element, such as flexible printedcircuit, “flex”, or “FPC” material.) Each of components 30 is shown ashaving two electrically conductive leads 32 extending from it. This isonly an example, and a component can have any number of such leads.Moreover, these leads can have any of a variety of shapes, as well asany of a variety of locations relative to the remainder of theassociated component 30. In the particular example shown in FIG. 1,leads 32 are shown as being intended for soldering to the upper surfaceof PCB 20 (e.g., to solder paste areas on that surface (see alsolater-described FIG. 3)). FIG. 1 also shows electrical ground contacts40 on the upper surface of PCB 20. FIG. 1 shows circuitry 10 before anysolder or any EMI shielding structure has been added to it.

FIG. 2 shows a structure like that shown in FIG. 1 from a lineapproximately like that indicated at 2-2 in FIG. 1. However, FIG. 2shows the structure after addition of EMI shielding 50 of a prior artkind. FIG. 2 shows this shielding 50 and some associated electricalinsulation 60 in section (taken along a line like 2-2 in FIG. 1), butFIG. 2 is otherwise primarily an elevational view.

FIG. 2 shows the placement of a metal cover 50 over components 30 and aportion of PCB 20. To ensure that metal cover 50 cannot cause a shortcircuit in the circuitry that it covers, a layer of electricalinsulation 60 is provided between cover 50 and the underlying circuitry30, etc. Cover 50 is electrically connected to ground contacts 40 on PCB20. For example, cover 50 may be soldered to these ground contacts.Accordingly, cover 50 provides EMI shielding for the electronic circuitcomponents 30 under or inside that cover.

FIG. 3 shows a structure like that shown in FIG. 1, but from anotherdirection (i.e., along the line 3-3 in FIG. 1). FIG. 3 shows a typicalelectronic circuit component 30 on solder paste regions 34 prior tosoldering of component 30 to PCB 20 (i.e., prior to so-called reflow).FIG. 3 shows additional ground contacts 40 beyond paste regions 34.

FIG. 4 shows the FIG. 3 structure again, but after reflow. As shown inFIG. 4, solder areas 36 now exist at the location of each solder pasteregion 34 in FIG. 3. Like FIG. 1, FIGS. 3 and 4 show the structurebefore any EMI shielding structure has been added.

FIG. 5 shows the FIG. 4 structure after addition of conventionalinsulation 60 and EMI shielding 50 of the type shown in FIG. 2. FIG. 6shows how the lower edge of EMI shielding 50 may be scalloped orcrenellated so that it can contact a plurality of spaced ground contacts40, while jumping over other circuitry (e.g., electrical circuit traceson PCB 20) between those contacts 40.

Note that in the prior art construction that is illustrated by FIGS. 2and 5, EMI shielding 50 has a predetermined size and shape that isbasically independent of the size and shape of the circuit components 30covered by that shielding. Moreover, shielding 50 holds thatpredetermined size and shape after it has been applied over components30 and their ancillary electrical features like 32 and 36. Note alsothat shielding 50 is typically manufactured separately from the elementsover which it is applied, and then this prefabricated shieldingstructure is added over the underlying electrical circuitry.

Because of tolerances required in manufacturing components 30 andrelated features 32 and 36, as well as tolerances required in separatelymanufacturing shielding 50 (and possibly also insulation 60), shielding50 must be made so that (at a minimum) its interior is larger than (at amaximum) the exterior of the underlying circuitry. This typically meansthat shielding 50 effectively increases the size of the finishedstructure by a significant amount (as compared to the size of theunderlying circuitry (e.g., 30, 32, and 36)). This may be undesirable incontexts in which an objective is to keep electronic circuit structuresas small as possible.

FIG. 7 shows an illustrative embodiment of how electronic circuitrycomponents 30, mounted on a PCB 20 as shown in FIGS. like 1, 3, and 4,may be shielded more compactly than in prior art such as FIGS. 2, 5, and6. In particular, FIG. 7 shows a starting structure like that shown inFIG. 4. Then a layer of conforming electrical insulation 160 is appliedover the FIG. 4 structure except for ground contacts 40. Thereafter, alayer of conforming, electrically conducting, EMI shielding 150 isapplied over insulation 160 so that the EMI shielding reaches and makescontact with ground contacts 40.

The term “conforming” as used herein with reference to insulation 160and EMI shielding 150 means that each of these layers follows, contacts,and preferably also adheres to the surface to which it is applied. Forexample, insulation 160 lays down on and intimately and extensivelycontacts the surface(s) of elements 30, 36, etc., to which it isapplied. Insulation 160 also preferably adheres to those surfaces.Insulation 160 is preferably applied with enough thickness to ensuregood electrical insulation to elements 30, 36, etc., but also preferablynot with greatly more thickness than is sufficient for that purpose.Insulation 160 can be applied in a liquid or at least a flowable fluidstate. For example, insulation 160 can be an epoxy resin (e.g., apotting compound) or a polymer (e.g., silicone rubber) that is brushedon over elements 30, 36, etc., or otherwise flowed on over thoseelements while in a liquid or at least flowable state. After insulation160 has been applied, it is converted to a non-fluid, non-flowablestate. For example, resin or polymer insulation 160 may be cured (e.g.,by time, temperature, and/or a chemical atmosphere) to render itnon-fluid and therefore non-flowable. Such curing may make insulatinglayer 160 hard, or it may still remain somewhat flexible.

As another example of how conforming insulation 160 may be applied,shrink-wrap type materials and procedures may be used for that purpose.Thus, for example, a sheet of shrink-wrappable insulating material maybe placed over elements 30, 36, etc. Then that material may be subjectedto the conditions that cause it to shrink-wrap down into much morecomplete, conforming contact with the surfaces of the elements 30, 36,etc., over which it has been placed. For example, these conditions maybe heat, a chemical environment, or anything else that activates theshrink-wrap properties of material 160. This causes insulation 160 tobecome conforming with (and also preferably to adhere to) the surfacesof elements 30, 36, etc., that it has been placed over. Such activationof the shrink-wrap properties of material 160 is a form of curing ofthat material, and it is embraced within the term curing (or the like)as that term is used herein.

After application of insulating layer 160 has been completed, EMIshielding layer 150 is applied over the insulation in a generallysimilar way. Thus shielding layer 150 is again a layer that conforms tothe surfaces to which it is applied (in this case the exposed surface ofinsulation 160, ground contacts 40, etc.). Shielding layer 150 is againapplied with sufficient thickness to enable it to perform its EMIshielding function, but preferably not with greatly more thickness thanthat. As a conforming layer, shielding layer 150 again follows andcontacts (and also preferably adheres to) the surfaces to which it isapplied. Application techniques like those described above for layer 160may be used again for layer 150 (employing, of course, an electricallyconducting material rather than an electrically insulating material).Thus, for example, an epoxy or polymer material that is loaded withmetal particles may be deposited on the surfaces below in a liquid or atleast a flowable fluid state. This may be done by brushing or otherwiseflowing this material (150) on over the surfaces below. Then material150 is converted to a non-fluid, non-flowable state. For example, thematerial of layer 150 may be cured (which may leave it hard or stillflexible to some degree) as described above for layer 160. As anotherexample, material 150 may be a shrink-wrappable sheet material. Such asheet is placed over the surfaces to be shielded, and then theshrink-wrap properties of the material may be activated to cause it toconform to (i.e., to contact, follow, and preferably adhere to) allportions of the surfaces to which it has been applied.

FIG. 7 of course shows the conforming nature of each of layers 160 and150 in the finished structure 10. Thus insulating layer 160 follows,contacts, and preferably adheres to all portions of the surfaces belowit (e.g., the upper surfaces of elements 30, 36, etc.). Similarly, EMIshielding layer 150 follows, contacts, and preferably adheres to allportions of the surfaces below it (e.g., the upper surfaces of elements160, 40, etc.). Especially of note is the fact that layer 150 makes goodelectrical contact with ground contacts 40 and provides an electricallycontinuous, electrically conductive cover over all elements below it.Layer 150 therefore provides EMI shielding for the circuitry covered byit.

Because elements 160 and 150 conform to the size and shape of theelements 30, 36, etc., that they cover, the resulting product (e.g., asin FIG. 7) can be smaller than prior art structures like FIGS. 2 and 5.The final product can have nearly the same size and shape as theunderlying electronic circuitry, increased only by the thickness oflayers 160 and 150.

FIGS. 8-10 illustrate an alternative embodiment of the invention inwhich one or more electronic circuit components are pre-shielded usingthe invention prior to being mounted on a substrate such as a PCB. ThusFIGS. 8 and 9 show elements 30 a-d assembled side-by-side, and coveredwith conforming insulation 160 and conforming EMI shielding 150 beforebeing mounted on a PCB. FIG. 10 then shows the assembly 200 of FIGS. 8and 9 (which assembly 200 may be referred to as a pre-shielded customcomponent pack) mounted on PCB 20. These FIGS. will now be described inmore detail.

In FIGS. 8 and 9, four electronic circuit components 30 a-d (which canbe like the similarly numbered elements in FIG. 1) are assembledside-by-side, with their leads 32 projecting from opposite sides of theassembly. A layer of conforming insulation 160 is then applied over theabove-mentioned assembly (except for the outer-most portions of leads 32and the underside of the assembly). Note that insulation 160 preferablydoes cover the inner-most portion of leads 32 as at 162 (but, again, notany portion of the lower surface of those leads). After insulation 160has been applied (and cured, if necessary), a layer of conforming EMIshielding 150 is applied over most of insulation 160. Note that theinsulation 162 on the inner portions of leads 32 prevents shielding 150from making electrical contact with leads 32. Note also that shielding150 is caused or allowed to form outward extensions 152 that can be usedto reach ground contacts when assembly 200 is later mounted on asubstructure such as a PCB. After shielding 150 has been applied, it iscured if necessary. Assembly 200 is now complete and ready for mountingon a substructure such as a PCB at any time. Such mounting isillustrated by FIG. 10, which will now be described.

FIG. 10 shows assembly 200 from FIGS. 8 and 9 mounted on PCB 20. Asolder paste area 34 is disposed on PCB 20 where each contact 32 willcome down on the PCB. Solder 36 is then applied to permanentlyelectrically and mechanically connect the exposed outer end portion ofeach lead 32 to electrical circuitry on the PCB. The same is done toconnect each of shielding tabs 152 to a ground contact on the PCB. Seealso FIG. 11, which shows a plan view of what is shown in FIG. 10 priorto the addition of solder 36. Thus FIG. 11 shows that there is a solderpaste area 34 under each of leads 32, and also under each of EMIshielding extensions 152. Solder 36 (e.g., as in FIG. 10) is added overeach of these solder paste areas 34 to connect the associated feature 32or 152 of assembly 200 to circuitry on PCB 20.

FIGS. 12 and 13 show an alternative embodiment in which there is somespacing between electronic circuit components 30 a-d in pre-shieldedcustom component pack 200′. In this embodiment the spacing betweencomponents 30 is filled by conforming insulation material 160. In allother respects assembly 200′ may be similar to assembly 200.

Any of the materials mentioned earlier for insulation 160 can be usedagain for the insulation 160 in embodiments like those illustrated byFIGS. 8-13. Also, the above-described techniques for applying (and, ifnecessary, curing) insulation 160 can be used again for the insulation160 in embodiments like those illustrated by FIGS. 8-13. The same istrue for EMI shielding 150 in embodiments like FIGS. 8-13 (i.e., any ofthe earlier-described EMI shielding 150 materials, applicationtechniques, and/or curing techniques (if necessary) can be used againfor the EMI shielding 150 in embodiments like FIGS. 8-13).

Alternative techniques for applying conforming insulation 160 and/orconforming EMI shielding 150 are illustrated by FIG. 14 and severalsubsequent FIGS. These alternative techniques involve molding insulation160 and/or shielding 150 around the structure(s) to be insulated and/orshielded. FIGS. 14 and 15 begin the illustration of these techniques byshowing an example of molding insulation 160 for a structure otherwisesimilar to what is shown in FIGS. 8 and 9. Thus in FIGS. 14 and 15elements 30 a-d and 32 are repeated from FIGS. 8 and 9.

FIGS. 14 and 15 show elements 30/32 placed inside a two-part moldstructure 300 a-b, which may be part of an injection molding machine. Inparticular, elements 30 a-d and 32 rest on lower mold part 300a, whichcontacts and covers the undersides of those elements. Upper mold part300 b is then placed over elements 30 a-b, 32, and 300 a. Upper moldpart 300 b peripherally sealingly contacts lower mold part 300 a, exceptwhere one or more openings like 302 may be left for injection ofinsulation 160 into the mold and/or for venting gas from the moldcavity. Upper mold part 300 b leaves a space (cavity) 304 between itsinner surface and all surfaces of assembly 30/32 that are to be coatedwith insulation 160. Note that upper mold part 300 b does not leave suchspace around the outer-most end portions of leads 32. Thus in areas like306, upper mold part 300 b fits closely around the outer end portions ofleads 32. However, space 304 does extend to around the inner portions ofleads 32 as shown, for example, at 308.

When elements 30/32 are positioned in mold 300 a-b as shown in FIGS. 14and 15, insulation material 160 in a flowable fluid condition isinjected (under pressure) into the space 304/308 around those elementsas indicated by the arrow 310 in FIG. 14. This causes insulation 160 tocompletely fill space 304/308 and conform to (and preferably also adhereto) all surfaces of elements 30/32 that were previously exposed to space304/308.

After insulation 160 has cured sufficiently (assuming that such curingis required), mold 300 a-b can be opened (by separating parts 300 a and300 b from one another), and subassembly 30/32/160 can be removed.Conforming EMI shielding 150 can now be added to this subassembly usingany of the techniques described earlier, or alternatively using afurther molding step as illustrated by FIG. 16, as will now bedescribed.

As shown in FIG. 16, the subassembly of elements 30/32/160 that comesout of molding process 300 a-b is placed in two-part mold 320 a-b, whichcan be part of another injection molding machine. In particular,subassembly 30/32/160 is placed on lower mold part 320 a, which again isshaped to cover the undersides of elements 30 and 32. Upper mold part320 b fits down over subassembly 30/32/160 and seals to lower mold part320 a all around subassembly 30/32/160, except for where apertures maybe left for such purposes as injecting EMI shielding material 150 intothe mold or allowing venting from the mold. The inner surface of uppermold part 320 b leaves a space (cavity) 324 between that surface and anypart of subassembly 30/32/160 that it is desired to cover with shielding150. The inner surface of upper mold part 320 b may also leave a similarspace between that surface and lower part 320 a where it is desired forshielding 150 to also form projections 152 for connection to groundcontacts on another structure like PCB 20.

Note that upper mold part 320 b is shaped (e.g., at 326) to fit snuglyaround outer portions of the insulation 162 that covers the innerportions of leads 32. This keeps the shielding material 150 that isinjected into cavity 324 from making contact with any of leads 32.

When subassembly 30/32/160 is in mold 320 a-b as shown in FIG. 16, EMIshielding material 150 in a flowable fluid state is injected (underpressure) into the space 324 that is left in the mold around selectedparts of subassembly 30/32/160 as shown in FIG. 16 and described above.This causes shielding material 150 to fill space 324, whereby itconforms to (and preferably also adheres to) the portions of subassembly30/32/160 that it is desired to shield. After shielding material 150 hascured sufficiently (assuming that such curing is necessary), the twoparts of mold 320 a-b can be separated, and finished assembly30/32/160/150 can be removed. It will be appreciated that this assemblycan look very much like assembly 200 in FIGS. 8 and 9, and that it canbe used in the same way that assembly 200 can be used.

The molding alternatives illustrated by FIGS. 14-16 can be used foreither insulation 160, or for shielding 150, or for both insulation 160and shielding 150. Molding may allow (or at least facilitate) the use ofdifferent materials for insulation 160 and/or shielding 150 than wouldotherwise be possible (or at least easy) to use. For example, moldingmay allow the use of molten metal (e.g., molten silver) for shielding150. As another example, molding may allow the use of certain plasticsor rubbers for insulation 160 that it would otherwise be difficult orimpossible to use. Molding may allow (or at least facilitate) moreprecise control of where insulation 160 and/or shielding 150 isdeposited on underlying structures. For example, precise shaping of theinsulation 162 around certain portions of leads 32 may be facilitated bymolding insulation 160. Similarly, ensuring that shielding 150 does notextend beyond the outer ends of insulation portions 162 may befacilitated by molding shielding 150. Molding may also help to ensurethat the molded layer or layers 160 and/or 150 have the desiredthickness at all locations on the underlying structure(s). Molding doesnot alter the fact that the molded layer or layers 160 and/or 150 are“conforming” as that term is defined above.

FIG. 17 illustrates the point that molding techniques like thosedescribed above can also be applied to circuit components that havealready been mounted on a substructure such as a PCB. FIG. 17 thereforeshows a subassembly like that shown in FIG. 7 (but without insulation160 or shielding 150). This subassembly is placed in a two-part mold 340a-b that is shaped for application of insulating material 160 to desiredparts of the subassembly. The resulting further subassembly (now withinsulation 160) can then be placed in further molding apparatus 360 a-bas shown in FIG. 18 for application of shielding material 150 to thatfurther subassembly. The resulting final assembly will be similar towhat is shown in FIG. 7, except that layers 150 and 160 will have beenapplied by molding rather than by other means.

Briefly recapitulating and in some respects extending some of theforegoing, electronic components on printed circuit boards may produceelectromagnetic interference (“EMI”) that can affect the performance ofnearby electronic systems. This “noise” can affect not just productsoutside the mechanical envelope, but systems inside the product as well.To assist in blocking the noise emitted by a component, such componentsare often covered by a thin-walled metal can. This can is then solderedto the printed circuit board and connected to ground planes within theboard.

The above-mentioned cans can be large and bulky compared to thecomponents they cover. These cans can also require insulation layers andlarge flat areas to which to attach. What is needed is a method forproducing smaller EMI-blocking features to allow space inside anenclosure to be better utilized. The present invention addresses such aneed.

For example, a circuit board that has completed SMT (wherein electroniccomponents are soldered to the board) can be placed in a custom mold(e.g., 340 a-b) into which insulating potting material 160 or the likeis injected to produce a thin covering of electrical insulation over theboard and the components to be shielded. Once cooled or otherwise cured(if necessary), the board is removed from this first mold and placed ina second mold (e.g., 360 a-b) into which silver or other appropriatemetal or material is injected to produce a thin, electrically conductingcoating over the potting or other insulating material. In a final(optional) stage, the part may be painted with a spray coating.

If desired, the final stage mentioned immediately above may be omittedand the metal or other EMI shielding layer may be molded with additionalmechanical features for such purposes as to provide rigidity, electricalcontact, heat transfer, etc. As another possible alternative, theimmediately above-mentioned final stage can use a third mold to injectplastic over the EMI shielding. This plastic can have additionalfeatures molded in to serve other mechanical needs.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. For example, the number, shapes, sizes, etc., of thecomponents 30 to which the invention is applied can be different fromwhat is shown in the drawings herein, which are intended to be onlygenerally illustrative of what can be done.

1. A method of shielding an electronic circuit component for electro-magnetic interference comprising: applying a layer of electrical insulation to at least part of a surface of the component, the insulation conforming to the surface to which it is applied; and applying a layer of electromagnetic shielding to at least part of a surface of the insulation, the shielding conforming to the surface to which it is applied.
 2. The method defined in claim 1 wherein the applying a layer of electrical insulation comprises: applying the electrical insulation in flowable fluid form to the at least part of the surface of the component; and converting the electrical insulation to non-fluid form after it has conformed to the surface to which it is applied.
 3. The method defined in claim 1 wherein the applying a layer of electro-magnetic shielding comprises: applying the shielding in flowable fluid form to the at least part of the surface of the insulation; and converting the electrical insulation to non-fluid form after it has conformed to the surface to which it is applied.
 4. The method defined in claim 1 wherein the applying the layer of electrical insulation comprises: placing the component in a mold; and injecting the electrical insulation into the mold.
 5. The method defined in claim 4 wherein the applying the layer of electro-magnetic shielding comprises: removing the component with the electrical insulation as a subassembly from the mold; placing the subassembly in a second mold; and injecting the electro-magnetic shielding into the second mold.
 6. The method defined in claim 1 wherein the applying the layer of electro-magnetic shielding comprises: placing the component, to which the electrical insulation has been applied, in a mold; and injecting the electro-magnetic shielding into the mold.
 7. The method define in claim 1 further comprising: prior to applying the layer of electrical insulation, mounting the component on a supporting structure.
 8. The method defined in claim 7 wherein the supporting structure comprises a printed circuit board.
 9. The method defined in claim 1 further comprising: after applying the layer of electro-magnetic shielding, mounting the component with the insulation and the shielding on a supporting structure.
 10. The method defined in claim 9 wherein the supporting structure comprises a printed circuit board.
 11. The method defined in claim 8 wherein the applying the layer of electrical insulation comprises: placing the component and the printed circuit board in a mold; and injecting the electrical insulation into the mold.
 12. The method defined in claim 11 wherein the applying the layer of electro-magnetic shielding comprises: removing the component and the printed circuit board with the electrical insulation as a subassembly from the mold; placing the subassembly in a second mold; and injecting the electromagnetic shielding into the second mold.
 13. The method defined in claim 8 wherein the applying the layer of electro-magnetic shielding comprises: placing the component and the printed circuit board, to which the electrical insulation has been applied, in a mold; and injecting the electro-magnetic shielding into the mold.
 14. The method defined in claim 7 wherein the supporting structure includes a ground contact, wherein the applying the layer of electrical insulation leaves the ground contact uncovered by the electrical insulation, and wherein the applying the layer of electromagnetic shielding causes the electromagnetic shielding to reach the ground contact.
 15. The method defined in claim 9 wherein the supporting structure includes a ground contact, and wherein the mounting comprises: electrically connecting the electro-magnetic shielding to the ground contact.
 16. The method defined in claim 15 wherein the applying the layer of electro-magnetic shielding comprises: giving the electro-magnetic shielding a projection that can be used to reach the ground contact.
 17. Electronic circuit apparatus comprising: an electronic circuit component; a layer of electrical insulation applied to at least part of a surface of the component so that the electrical insulation covers, conforms to, follows, contacts, and adheres to said at least part of the surface of the component; and a layer of electro-magnetic shielding applied to at least part of a surface of the electrical insulation so that the electro-magnetic shielding covers, conforms to, follows, contacts, and adheres to said at least part of the surface of the electrical insulation, wherein the layer of electro-magnetic shielding is electrically conductive, and wherein a portion of the electro-magnetic shielding extends to a ground contact of a printed circuit board on which the electronic circuit component is mounted.
 18. The apparatus defined in claim 17 wherein a portion of the electrical insulation extends to the printed circuit board.
 19. (canceled)
 20. The apparatus defined in claim 18 wherein the ground contact is uncovered by the electrical insulation.
 21. (canceled)
 22. The apparatus defined in claim 17 wherein a subassembly of the electronic circuit component, the layer of electrical insulation, and the layer of electro-magnetic shielding is adapted for application to the printed circuit board.
 23. The apparatus defined in claim 22 wherein the electromagnetic shielding is formed with a projection for reaching the ground contact when the subassembly is applied to the printed circuit board. 